Firstly, thank you very much for the mod!
Even though the mod says "Cleaning decoratives from. concrete/brick/etc" it didn't place any, anywhere.

Found the problem. Instead of surface.destroy_decoratives({{x,y},{x,y}}) the mod should use surface.destroy_decoratives{position=t.position}.

In which file/line is that?

I created a fix for this (see RePainter-Zenorbi) and also did some improvements to not remove every decorative. Decorative removal is chance based when you place your tiles.

I've updated the version to fix both the tile and rail decorative issues for 0.17

BTW feel free to copy my modifications, I did not intend to fork this project, just played with it out of curiosity and uploaded the code once it was good for me. You can treat it as a pull request :)

Main modifications are:
- Chance based decorative removal
- IMO nicer async loop
- Moved the starting area lake out of the way, so no more starting lake in the middle of your factory
- Handled hidden tiles (tiles under concrete and stuff)